Immune modulation device for use in animals

ABSTRACT

The present invention is directed to an implantable immune modulation device that is useful for modulating an immune response in mammals, comprising a plurality of fibers, within a porous shell. The fiber filling is loaded with single or multiple antigens, and optionally one or more biologically active compounds such as cytokines (e.g. lymphokines, chemokines etc.), attachment factors, genes, peptides, proteins, nucleotides, carbohydrates or cells depending on the application.

[0001] This application claims benefit of provisional patent applicationNo. 60/290,542 filed May 11, 2001, which is hereby incorporated byreference herein.

FIELD OF THE INVENTION

[0002] The present invention relates to an implantable device and methodfor modulating the immune response to antigens in mammals. Morespecifically the present invention provides a porous, implantable devicecontaining a fibrous support and at least one antigen. This device maybe used to modulate the immune system to provide a robust responseagainst an antigen, or to down regulate an existing response.

BACKGROUND OF THE INVENTION

[0003] Induction of an immune response to an antigen and the magnitudeof that response depend upon a complex interplay among the antigen,various types of immune cells, and co-stimulatory molecules includingcytokines. The timing and extent of exposure of the immune cells to theantigen and the co-stimulatory milieu further modulate the immuneresponse. Within the body, these various cell types and additionalfactors are brought into proximity in lymphoid tissue such as lymphnodes. Of the numerous cell types involved in the process,antigen-presenting cells (APC), such as macrophages and dendritic cells,transport antigen from the periphery to local, organized lymphoidtissue, process the antigen and present antigenic peptides to T cells aswell as secrete co-stimulatory molecules. Thus, if antigen reaches lymphorgans in a localized staggered manner, presenting antigenic epitopes,under the optimal concentration gradient and under the appropriateenvironment comprising co-stimulatory molecules, a response is inducedin the draining lymph node.

[0004] In this manner, a foreign antigen introduced into the body, suchas by means of a vaccination, may or may not result in the developmentof a desirably robust immune response. Antigens used for vaccinationinclude attenuated and inactivated bacteria and viruses and theircomponents. The success of vaccination depends in part on the type andquantity of the antigen, the location of the site of immunization, andthe status of the immune system at the time of vaccination. Not allantigens are equally immunogenic, and for poorly immunogenic antigens,there are few alternatives available to increase the effectiveness ofthe immunization. Whereas in experimental animals numerous techniquesare available to enhance the development of the immune response, such asconjugating the antigen to a more immunogenic carrier protein orbiomolecule (e.g., keyhole limpet hemocyanin), or the use of adjuvantssuch as Freund's Adjuvant or Ribi. For human vaccinations suchtechniques and adjuvants are not available. Thus, numerous diseases thatwould otherwise be preventable by vaccination before exposure to theinfectious agent, or in the case of a therapeutic vaccine, that mayinduce the development of an effective immune response to an existingdisease-causing agent or cell, such as cancer, are not available to thepatient.

[0005] Sponge implant studies have been performed in mammals to assessthe immune cell population attracted to a foreign body, which producewhat is called a sterile abscess, and sponges prior to or afterimplantation have been loaded with antigen to further study theattracted cell population. Vallera et al. (1982, Cancer Research42:397-404) implanted sponges containing tumor cells in mice to examinethe composition of cells attracted over a 16 day period, and found thatat an early time, cytotoxic cell precursors were present, andcytotoxicity peaked at day 16. Sponges containing tumor cells implantedin mice that had been previously immunized with tumor cells showed amore rapid appearance of cytotoxic cells in the sponge. In neither casedid cells from the spleen, lymph nodes or peritoneum show cytotoxicity,which suggested a highly localized response to the antigen in thesponge. Zangemeister-Wittke et al. (1989, J. Immunol. 143:379-385)injected a tumor vaccine into sponges implanted in tumor-immune mice,and monitored the generation of a secondary immune response at thesponge site. No accompanying effect was apparent in lymph nodes adjacentto the implanted sponge.

[0006] Other devices which overcome some of the limitations of spongesfor immunomodulation have been proposed. U.S. Pat. No. 4,919,929 teachesthat an antigen can be loaded into solid shaped particles, which slowlyrelease the antigen following implantation. This type of device isenvisaged to increase the antibody titers in the milk of mammals andthereby confer higher levels of immunity in those who consume it. WOapplication 93/17662 describes a device that consists of an imperviousmembrane surrounding a core, which is a gel loaded with atherapeutically active ingredient (including antigens). There is atleast one port in the impervious membrane that is capable of releasingthe active to the surroundings. The use of the membrane is shown to slowthe rate of release of the bioactive molecule (including antigens)relative to the gel alone. This device therefore primarily serves as areservoir for slow release and does not facilitate the interaction ofcells with the bioactive, which necessarily must occur outside of thedevice. In U.S. Pat. No. 4,732,155, a device is proposed where there isa reservoir that provides prolonged release of a chemoattractant, whichis surrounded by a web of fibers adjacent to the reservoir. Cells areattracted to the reservoir and become trapped in the fibrous web. Thisdevice is proposed for use in characterizing allergic and inflammatoryresponses to test compounds by allowing controlled exposure to thecompound and by trapping the cells that respond to it. This device bothincorporates a mechanism for prolonged exposure to an antigen as well asa mechanism to facilitate cellular interaction with the antigen. Theopen web of fibers in this device; however, does not enable localretention of the cytokines and chemokines being secreted by theresponding cells since an open web of fibers will not providediffusional resistance to soluble factors.

[0007] This design is improved upon in WO 99/44583 which proposes aporous matrix which is housed in a perforated but otherwise imperviousmembrane. Antigen is loaded within the device and can be present eitheras native antigen or can be encapsulated in a slow releasing polymerthat provides prolonged presentation of the antigen. Specific cells areattracted to the device by diffusion of the antigen from theperforations in the device and are also able to enter the device throughthe perforations, but the membrane provides sufficient diffusionalresistance that cytokines secreted by cells become locally concentratedwithin the device. The high local densities of cells and cytokinesproduce a much more robust immune response than is seen with anuncontained matrix or with simple prolonged release to surroundingtissues.

[0008] The preferred embodiment of the device mentioned above envisagesthe porous matrix to be a sponge and the membrane to be a perforatedtube. While very favorable immunomodulation is seen with the device, itis impractical to miniaturize and manufacture in large quantities. Theprimary reason is that it is very difficult to load a porous sponge intotubing. Sponges, due to their low bulk densities are mechanically weakand tend to tear easily when subjected to the tensile and compressiveforces of loading into small diameter tubing. By reducing the bulkdensity, more favorable mechanical properties can be encountered howeverthe matrix does not contain sufficient porosity to attain high celldensities. In addition, it is very difficult to cut small cylindricalcores of porous sponges for loading into tubes. The reason is that thepoor mechanical properties of the porous sponge lead to tearing when thesize of the piece being cut becomes very small. Consequently, the deviceenvisaged in WO 99/44583 is only practical to make in diameters ofgreater than 1 mm. Implantation of such a large profile device requiresa very sizable needle or trochar that would be very painful and causesignificant local trauma to a patient. An additional problem with thisdevice design is that it would be difficult to economically manufacturein large quantities. The reason is that each piece of sponge would needto be individually cut and stuffed into the tube. This would be verydifficult to mechanize and perform rapidly.

[0009] Accordingly, it would be advantageous to provide an implantabledevice and method for modulating an immune response to specific antigensin mammals, similar in concept to the design described in WO 99/44583,whose filling preserves the porosity presented by a porous sponge, whichis essential for rapid cellular infiltration, yet overcomes themechanical frailties of a sponge.

SUMMARY OF THE INVENTION

[0010] The present invention is directed to an implantable immunemodulation device that is suitable for use in modulating an immuneresponse in mammals, comprising an impermeable shell having a pluralityof pores and said impermeable biocompatible shell having an interiorlumen, a biocompatible fibrous scaffolding being disposed within saidinterior lumen. The fibrous scaffolding is loaded with single ormultiple antigens and optionally one or more biologically activecompounds such as cytokines (e.g. lymphokines, chemokines etc.),non-cytokine leukocyte chemotactic agents, attachment factors, genes,peptides, proteins, nucleotides, carbohydrates, or cells depending onthe application. The shell of the device preferably is made from apolymer whose glass transition temperature is below physiologictemperature so that the device will minimize irritation when implantedin soft tissues. The shell allows cell ingress but hinders diffusion ofsoluble molecules out of the device. This helps to concentrate cytokines(e.g. lymphokine and chemokines) secreted by cells which have enteredthe device in response to loaded antigens and other cells which arepresent in the device. This local concentration of cells and cytokinessignificantly enhances the immune response relative to implantation ofantigens with standard adjuvants. The fibrous scaffolding provides ascaffold for cells to reside on, process the antigens and interact.

[0011] Additional benefits of the fibrous scaffolding disclosed in thisinvention include ease of miniaturization of a device to diameters ofless than 1 mm, the possibility of rapid insertion into small diametertubing or even the ability to have tubing continuously extruded aroundthe matrix.

BRIEF DESCRIPTION OF THE FIGURES

[0012]FIG. 1 is a perspective drawing of one embodiment of the immunemodulating device described herein.

[0013]FIG. 2 is a scanning electron micrograph of one embodiment of atextured fiber suitable for use in the present invention made by theprocess described in Example 1.

[0014]FIG. 3 is a perspective drawing of one embodiment of the immunemodulating device showing one end of the device being sealed.

[0015]FIG. 4 is a perspective drawing of one embodiment of the immunemodulating device showing a device that is crimped.

[0016]FIG. 5 is a perspective drawing of one embodiment of the immunemodulating device showing one end of the device being crimped andsealed.

DETAILED DESCRIPTION OF THE INVENTION

[0017] An immune modulation device is disclosed herein which allows forcell ingress and concentration of cytokines secreted by cells. Aperspective view of the immune modulation device is provided in FIG. 1.The immune modulation device 2 is comprised of a shell 4 surrounding aninterior lumen 10. The shell 4 has pores 6 that extend from the outersurface 8 to the interior lumen 10. The interior lumen will have avolume of at least 1×10⁻⁸ cm³, preferably will be at least 3×10⁻⁸ cm³and most preferably the size of the lumen will be sufficient to elicitthe desired immune response from the animal in which it is implanted(which can be determined by methods well known in the art such asELISA). The shell 2 may have a variety of three dimensional shapes (e.g.cylindrical, spherical, rectangular, rhomboidal, etc.). For example theshell 2 will generally have a longitudinal axis and a cross-section thatmay be circular, oval or polygonal. Preferred for ease of manufacture isa cylindrical shape. A cylindrically shaped immune modulation device 2is illustrated in FIG. 1. The ends of the cylindrically shaped immunemodulation device may be capped or left open as illustrated in FIG. 1.The outer surface 8 of the immune modulation device 2 is preferablyimpervious to cytokines and immune cells and has numerous pores 6 thatallow for the ingress and egress of immune cells. The number of pores 6will generally be less than 25 percent of the outer surface andpreferably will be less than about 10 percent of the outer surface. Thepores 6 size may range from about 10 to about 500 microns and preferablyin the range of from about 100 to about 400 microns. The interior 10 ofimmune modulation device 2 will be filled with a fibrous scaffolding 12made of a plurality of fibers (e.g. a yarn or a tow).

[0018] The fibrous scaffolding 12 is made from biocompatible fibers,preferably textured fibers which provide a much lower bulk densityfilling than non-texturized fiber. The low bulk density of texturedfibers enables rapid population of the immune modulation device 2 withsignificant numbers of cells and helps to retain the fibrous scaffolding12 within the shell 4. The fibrous scaffolding 12 is loaded with singleor multiple antigens and optionally other biologically active orpharmaceutically active compounds (e.g. cytokines (e.g. interlukins1-18; interferons α, β, and γ; growth factors; colony stimulatingfactors, chemokines, tumor necrosis factor α and β, etc.), non-cytokineleukocyte chemotactic agents (e.g. C5a, LTB₄, etc.), attachment factors,genes, peptides, proteins, nucleotides, carbohydrates or syntheticmolecules) or cells depending on the application.

[0019] The shell 4 and the fibrous scaffolding 12 of the device will bemade with a biocompatible material that may be absorbable ornon-absorbable. The device will preferably be made from biocompatiblematerials that are flexible and thereby minimizing irritation to thepatient. Preferably the shell will be made from polymers or polymerblends having glass transition temperature below physiologictemperature. Alternatively the device can be made with a polymer blendedwith a plasticizer that makes it flexible.

[0020] In theory but in no way limiting the scope of this invention itis suspected that the shell allows cell ingress and egress but hindersdiffusion of soluble molecules out of the device. This is believed tohelp to concentrate cytokines secreted by cells that have entered thedevice in response to loaded antigens (e.g. antigen presenting cells)and other cells (e.g. helper T cells, B cells etc.) which are present inthe device. The fibrous scaffolding provides a scaffold for cells toreside on and process the antigens. This local concentration of cellsand cytokines significantly enhances the immune response relative toimplantation of antigens with standard adjuvants.

[0021] The intended recipient of the implantable device is an animal;preferably a human, but also including livestock animal, (e.g. sheep,cow, horse, pig, goat, lama, emu, ostrich or donkey), poultry (e.g.chicken, turkey, goose, duck, or game bird), fish (e.g. salmon orstrugeon), laboratory animal (e.g. rabbit, guinea pig, rat or mouse)companion animal (e.g. dog or cat) or a wild animal in captive or freestate.

[0022] Numerous biocompatible absorbable and nonabsorbable materials canbe used to make the shell or fibrous scaffolding. Suitable nonabsorbablematerials for use in as the shell or fibrous scaffolding include, butare not limited to, polyamides (e.g. polyhexamethylene adipamide (nylon6,6), polyhexamethylene sebacamide (nylon 610), polycapramide (nylon 6),polydodecanamide (nylon 12) and polyhexamethylene isophthalamide (nylon61), copolymers and blends thereof), polyesters (e.g. polyethyleneterephthalate, polybutyl terphthalate (e.g. as described in EPA 287,899and EPA 448,840), copolymers (e.g. as described in U.S. Pat. No.4,314,561; Re 32,770; U.S. Pat. Nos. 4,224,946; 5,102,419 and 5,147,382)and blends thereof), fluoropolymers (e.g. polytetrafluoroethylene andpolyvinylidene fluoride copolymers (e.g. as described in U.S. Pat. No.4,564,013) and blends thereof), polyolefins (e.g. polypropyleneincluding atactic but preferably isotactic and syndiotacticpolypropylene and blends thereof, as well as, blends composedpredominately of isotactic or syndiotactic polypropylene blended withheterotactic polypropylene and polyethylene), organosiloxanes (e.g.polydimethylsiloxane rubber such as SILASTIC® silicone tubing from DowCorning), polyvinyl resins (e.g. polystyrene, polyvinylpyrrolidone,etc.) and blends thereof.

[0023] Additionally the fibrous scaffolding may be made from naturalfibers such as cotton, linen and silk (although silk is referred to as anonabsorbable material, it is broken down in the human body). Raw silkconsists of two filaments that are held together by seracin (silk glue).The silk is degummed (the seracin is removed) and the resulting singlefilaments are used to manufacture the fiber. The denier per filament(dpf) of individual silk fibers will range from about 0.8 to about 2.0.For fiber manufacture it is common to used silk with a dpf of from about0.8 to about 1.6 and more preferably a dpf of from about 0.8 to about1.4. The best grades of silk are easily obtainable from suppliers inChina and Japan.

[0024] Polyesters are also well known commercially available syntheticpolymers that may be used to make the shell or fibrous scaffolding. Themost preferred polyester for making this device is polyethyleneterephthalate. Generally, polyethylene terephthalate polymers used tomake fibers will have a weight average molecular weight of greater than30,000 preferably greater than 40,000 and most preferably in the rangeof from about 42,000 to about 45,000. The filaments formed from thesepolymers should have a tenacity of greater than 5 grams/denier andpreferably greater than 7 grams/denier. Polyethylene terephthalate yarnsare commonly available from a variety of commercial fiber suppliers(such as E.I. DuPont and Hoechst Celanese). Preferred are commerciallyavailable fibers that may be purchased from Hoechst Celanese under thetrademark TREVIRA® High Tenacity type 712 and 787 polyester yarns.

[0025] A variety of fluoropolymers may also be used to make the shelland the fibrous scaffolding such as polytetrafluoroethylene andpolyvinylidene fluoride (i.e. as in U.S. Pat. No. 4,052,550), copolymersand blends thereof. Currently the preferred are the fluoro polymersblends of polyvinylidene fluoride homopolymer and polyvinylidenefluoride and hexafluoropropylene copolymer which is described in U.S.Pat. No. 4,564,013 hereby incorporated by reference herein.

[0026] As previously stated the term polypropylene for the purposes ofthis application include atactic but will be preferably isotactic andsyndiotactic polypropylene (such as is described in U.S. Pat. No.5,269,807 hereby incorporated by reference herein) and blends thereof,as well as, blends composed predominantly of isotactic or syndiotacticpolypropylene blended with heterotactic polypropylene and polyethylene(such as is described in U.S. Pat. No. 4,557,264 issued Dec. 10, 1985assigned to Ethicon, Inc. hereby incorporated by reference) andcopolymers composed predominantly of propylene and other alpha-olefinssuch as ethylene (which is described in U.S. Pat. No. 4,520,822 issuedJun. 4, 1985 assigned to Ethicon, hereby incorporated by reference). Thepreferred polypropylene material for making fibers is isotacticpolypropylene without any other polymers blended or monomerscopolymerized therein. The preferred method for preparing the flexiblepolypropylene fibers of the present invention utilizes as the rawmaterial pellets of isotactic polypropylene homopolymer having a weightaverage molecular weight of from about 260,00 to about 420,000.Polypropylene of the desired grade is commercially available in bothpowder and pellet form.

[0027] A variety of bioabsorbable polymers can be used to make the shellor fibrous scaffolding of the present invention. Examples of suitablebiocompatible, bioabsorbable polymers include but are not limited topolymers selected from the group consisting of aliphatic polyesters,poly(amino acids), copoly(ether-esters), polyalkylenes oxalates,polyamides, tyrosine derived polycarbonates, poly(iminocarbonates),polyorthoesters, polyoxaesters, polyamidoesters, polyoxaesterscontaining amine groups, poly(anhydrides), polyphosphazenes,biomolecules (i.e., biopolymers such as collagen, elastin, bioabsorbablestarches, etc.) and blends thereof. For the purpose of this inventionaliphatic polyesters include, but are not limited to, homopolymers andcopolymers of lactide (which includes lactic acid, D-, L- and mesolactide), glycolide (including glycolic acid), ε-caprolactone,p-dioxanone (1,4-dioxan-2-one), trimethylene carbonate(1,3-dioxan-2-one), alkyl derivatives of trimethylene carbonate,delta-valerolactone, beta-butyrolactone, gamma-butyrolactone,ε-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one(including its dimer 1,5,8,12-tetraoxacyclotetradecane-7,14-dione),1,5-dioxepan-2-one, 6,6-dimethyl-1,4-dioxan-2-one, 2,5-diketomorpholine,pivalolactone, gamma, gamma-diethylpropiolactone, ethylene carbonate,ethylene oxalate, 3-methyl-1,4-dioxane-2,5-dione,3,3-diethyl-1,4-dioxan-2,5-dione, 6,8-dioxabicycloctane-7-one andpolymer blends thereof. Poly(iminocarbonates), for the purpose of thisinvention, are understood to include those polymers as described byKemnitzer and Kohn, in the Handbook of Biodegradable Polymers, edited byDomb, et. al., Hardwood Academic Press, pp. 251-272 (1997).Copoly(ether-esters), for the purpose of this invention, are understoodto include those copolyester-ethers as described in the Journal ofBiomaterials Research, Vol. 22, pages 993-1009, 1988 by Cohn and Younes,and in Polymer Preprints (ACS Division of Polymer Chemistry), Vol.30(1), page 498, 1989 by Cohn (e.g. PEO/PLA). Polyalkylene oxalates, forthe purpose of this invention, include those described in U.S. Pat. Nos.4,208,511; 4,141,087; 4,130,639; 4,140,678; 4,105,034; and 4,205,399hereby incorporated by reference herein. Polyphosphazenes, co-, ter- andhigher order mixed monomer-based polymers made from L-lactide, D,L-lactide, lactic acid, glycolide, glycolic acid, para-dioxanone,trimethylene carbonate and epsilon-caprolactone such as are described byAllcock in The Encyclopedia of Polymer Science, Vol. 13, pages 31-41,Wiley Intersciences, John Wiley & Sons, 1988 and by Vandorpe, et al inthe Handbook of Biodegradable Polymers, edited by Domb, et al, HardwoodAcademic Press, pp. 161-182 (1997). Polyanhydrides include those derivedfrom diacids of the form HOOC—C₆H₄—O—(CH₂)_(m)—O—C₆H₄—COOH, where m isan integer in the range of from 2 to 8, and copolymers thereof withaliphatic alpha-omega diacids of up to 12 carbons. Polyoxaesters,polyoxaamides and polyoxaesters containing amines and/or amido groupsare described in one or more of the following U.S. Pat. Nos. 5,464,929;5,595,751; 5,597,579; 5,607,687; 5,618,552; 5,620,698; 5,645,850;5,648,088; 5,698,213; 5,700,583; and 5,859,150 hereby incorporatedherein by reference. Polyorthoesters such as those described by Hellerin Handbook of Biodegradable Polymers, edited by Domb, et al, HardwoodAcademic Press, pp. 99-118 (1997).

[0028] As used herein, the term “glycolide” is understood to includepolyglycolic acid. Further, the term “lactide” is understood to includeL-lactide, D-lactide, blends thereof, and lactic acid polymers andcopolymers.

[0029] Particularly well suited for use in the present invention arebiocompatible absorbable polymers selected from the group consisting ofaliphatic polyesters, copolymers and blends which include but are notlimited to homopolymers and copolymers of lactide (which includes D-,L-, lactic acid and D-, L- and meso lactide), glycolide (includingglycolic acid), epsilon-caprolactone, p-dioxanone (1,4-dioxan-2-onewhich is described in U.S. Pat. No. 4,052,988 incorporated herein byreference herein), alkyl substituted derivatives of p-dioxanone (i.e.6,6-dimethyl-1,4-dioxan-2-one which is described in U.S. Pat. No.5,703,200 assigned to Ethicon and hereby incorporated by reference),trimethylene carbonate (1,3-dioxan-2-one), alkyl substituted derivativesof 1,3-dioxanone (which are described in U.S. Pat. No. 5,412,068incorporated herein by reference), delta-valerolactone,beta-butyrolactone, gamma-butyrolactone, epsilon-decalactone,hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one (described in U.S.Pat. No. 4,052,988 and its dimer1,5,8,12-tetraoxacyclotetradecane-7,14-dione which is described in U.S.Pat. No. 5,442,032 assigned to Ethicon and hereby incorporated herein byreference), 1,5-dioxepan-2-one, and polymer blends thereof. Preferredfiber materials include but are not limited to copolymers oftrimethylene carbonate, epsilon-caprolactone and glycolide (such as aredescribed in U.S. Pat. Nos. 5,431,679 and 5,854,383 hereby hereinincorporated by reference) and copolymers of p-dioxanone, trimethylenecarbonate and glycolide and copolymers of lactide and p-dioxanone.Preferred are fibers made from lactide and glycolide sometimes referredto herein as simply homopolymers and copolymers of lactide and glycolideand copolymers of glycolide and epsilon-caprolactone i.e. as describedin U.S. Pat. Nos. 5,133,739; 4,700,704 and 4,605,730 incorporated hereinby reference), most preferred for use as a fiber is a copolymer that isfrom about 80 weight percent to about 100 weight percent glycolide withthe remainder being lactide. More preferred are copolymers of from about85 to about 95 weight percent glycolide with the remainder beinglactide.

[0030] The molecular weight of the polymers used in the presentinvention can be varied as is well know in the art to provide thedesired performance characteristics. However, it is preferred to havealiphatic polyesters having a molecular weight that provides an inherentviscosity between about 0.5 to about 5.0 deciliters per gram (dl/g) asmeasured in a 0.1 g/dl solution of hexafluoroisopropanol at 25° C., andpreferably between about 0.7 and 3.5 deciliters per gram (dl/g).

[0031] As mentioned above, the outer surface 8 of shell 4 will beperforated with pores 6, which provide a passageway for the ingress andegress of cells to the interior lumen 10 of the immune modulation device2. At the time of implantation the shell 2, is substantially impermeableto diffusion of water through the non-perforated walls of the shell. Theshell 2 is preferably made from one or more absorbable polymers that maybecome more permeable to aqueous media as they degrade. Absorbablepolymers can either be of natural or synthetic origin. The absorbablepolymers for the membrane most preferably have a glass transitiontemperature below physiologic temperature and would therefore be lessirritating when implanted in soft tissues. Preferred polymers for theshell would include copolymers with a significant content (at least 30weight percent) of epsilon-caprolactone or para-dioxanone. Aparticularly desirable composition includes an elastomeric copolymer offrom about 35 to about 45 weight percent epsilon-caprolactone and fromabout 55 to about 65 weight percent glycolide, lactide (or lactic acid)and mixtures thereof. Another particularly desirable compositionincludes para-dioxanone homopolymer or copolymers containing from about0 to about 80 weight percent para-dioxanone and from about 0 to about 20weight percent of either lactide, glycolide and combinations thereof.The degradation time for the membrane in-vivo is preferably longer than1 month but is shorter than 6 months and more preferably is longer than1 month but less than 4 months.

[0032] The shell 4 can be of any shape into which the fibrousscaffolding can be placed. The shell can initially have openings thatmay be later sealed following placement of the fibrous scaffolding 12.The shell 4 can be made by conventional polymer processing techniquesincluding molding, welding, casting, extrusion, injection molding,machining process or combinations thereof. These conventional proceduresare well known in the art and described in the Encyclopedia of PolymerScience and Engineering, incorporated herein as reference. Meltextrusion is the preferred method of process as it is rapid,inexpensive, scalable, and can be performed solvent-free for manypolymers of interest. Processing aides and plasticizers can be added tothe polymer to decrease the processing temperature and/or modify thephysical properties of the construct. Processing aides, such assolvents, can be added to decrease the processing temperature bydecreasing the glass transition temperature of the polymer.Subsequently, the aide can be removed by either heat and/or vacuum or bypassing the extruded construct through a secondary solvent in which thepolymer has minimal solubility but is miscible with the processing aide.For example halogenated solvents such as methylene chloride orchloroform can be added to homo- and copolymers of lactide andepsilon-caprolactone. After extrusion, the solvent can be removedthrough evaporation, vacuum, and/or heat. These solvents could also beextracted by passing the extrudate through a secondary solvent such asalcohol, which has miscibility with the halogenated solvent.Plasticizers can also be incorporated into a polymer to increase itsworkability, flexibility, or distensibility. Typically these materialswork by increasing the free volume of the polymer. For example manycitrates, malates and caprilates will work to plasticize many aliphaticpolyesters. Oligomers of a given polymer or copolymer can also be usedto plasticize a system.

[0033] The preferred shapes of the shell are those with a minimaldiameter in one dimension to facilitate placement using a small gaugeneedle. A most preferred shape is a cylinder with an outer diameterpreferably less than 1 millimeter and most preferably less than 750microns. This shape and size facilitates implantation of the deviceusing an 18 gauge needle or smaller. For this embodiment it is preferredthat the wall thickness is preferably less than 250 microns and mostpreferably is less than 150 microns. The pores 6 in the shell 4generally are large enough to provide for the ingress and egress ofcells. The pores are preferably larger than about 10 microns but smallerthan about 500 microns in cross-sectional diameter and more preferablyare from about 100 to about 400 microns in cross-sectional diameter. Thedensity of perforations preferably does not exceed 25% of the outersurface area of the device and more preferably is below 10% of the outersurface area of the shell of the immune modulation device. The pores canbe formed using any appropriate drilling technique (e.g. using ahypodermic needle, mechanical or laser) or alternatively by including asolvent or water soluble solid in the wall polymer which later can beleached out by immersing the tube in the solvent to generate the hole.Alternatively, if biocompatible water soluble particles such as sugars,amino acids, polymers such as PVP, proteins such as gelatin,carbohydrates such as hyalyronic acid and certain carboxymethylcelluloses are used, the device can be implanted with theparticles present. Upon exposure to body fluids the pore formingparticles can leach out or degrade forming pores. Most of the pore mustextend completely through the wall of the device and provide a pathwayfor cells involved in the immune response to ingress into the interiorlumen 10 of the device as well as for antigen and cytokines to diffuseout of the interior lumen 10 of the immune modulation device 2. If theimmune modulation device 2 has one or more open ends 14 of the immunemodulation device can either be sealed with layer 16 or left open, butare preferably left open. One embodiment of an immune modulation devicewith one sealed end is illustrated in FIG. 3.

[0034] In another embodiment of the present invention two portions ofthe interior surface 18 may contact the fibrous scaffolding 12 torestrain movement of the fibers in the immune modulation device 2. Forexample if the immune modulation device 2 were cylindrical a portion ofthe device could be crimped about the fibrous scaffolding 12. Thecrimping could be performed with heating to permanently reshape aportion of the shell 4. One embodiment of a crimped device isillustrated in FIG. 4. Alternatively, the crimping could be performedwith cutting and sealing one end of the immune modulation device 2 toform a cylindrical device with one sealed end 20. One embodiment of thisdevice with a sealed end is illustrated in FIG. 5.

[0035] Fibers suitable for use in the present device can be made usingconventional spinning processes such as melt spinning processes orsolution spinning. After spinning the yarns may be quenched, treatedwith a spin finish, drawn and annealed as is known in the art. Thefibrous scaffolding made from these fibers should have a porosity ofgreater than 20%, more preferably from about 25% to about 95%, and mostpreferably from about 30% to about 90% to the fibers.

[0036] The fibrous scaffold should be made up of filaments having adenier in the range of from about 0.2 to about 10 and preferably adenier from about 0.8 to about 6 and more preferably a denier of fromabout 1 to about 3. The filaments are commonly extruded in bundles(yarns) having a denier in the range of from about 20 to about 400denier and preferably about 50 to about 100 denier. The fibers need tobe treated to develop the bulk density or porosity need for a fibrousscaffold. The preferred yarns for this application are textured yarns.There are many forms of textured yarns that may be used to form afibrous scaffolding such as bulked yarns, coil yarns, core bulked yarns,crinkle yarns, entangled yarns, modified stretch yarns, nontorquedyarns, set yarns, stretch yarns and torqued yarns and combinationsthereof. Methods for making these yarns are well known and include thefalse-twisted method, entanglement (e.g. rotoset or air jet entangled),crimping (e.g. gear crimped, edge crimped or stuffer box crimped), andknit-de-knit. Preferably the fibers will be textured by false-twistingmethod, the stuffer box method or knit-de-knit method of textiletexturing. The filaments are texturized to provide a high degree ofpermanent crimping or random looping or coiling. Crimped fibers arecurrently preferred. Crimping causes the orientation of the filament tochange angle at the crimping points. The angle change is preferablygreater than 10 degrees at each crimp point. The crimping can beaccomplished through a variety of processes but is most easily generatedby feeding the extruded filaments through a stuffer box.

[0037] The fibrous scaffolding is preferably a texturized fiber madefrom an absorbable polymer that can either be of natural or syntheticorigin. Each fiber filament preferably has a diameter of less than 20microns and most preferably less than 15 microns. This imparts to thefilaments sufficient flexibility to completely fill the lumen of thetube and provide a suitable surface for cells to colonize in the lumenof the shell. The fibers preferably will take longer than 1 month tobiodegrade (via hydrolysis and/or enzymatic activity) in a normalsubcutaneous implantation but will completely be biodegraded within 6months and more preferably between 1 and 4 months. An example of a goodpolymer for making a fibrous scaffolding is a copolymer of 90% glycolide(or glycolic acid) and 10% lactide (or lactic acid) having an inherentviscosity between about 0.7 to about 1.5 deciliters per gram (dl/g) asmeasured in a 0.1 g/dl solution of hexafluoroisopropanol at 25° C.

[0038] The most significant advantage with the use of fibrousscaffolding is that the fibers can be easily placed within the shell.For example, a textured fiber can be stretched and then the shellextruded, molded or otherwise coated of shaped around them. Followingplacement of the shell around the stretched fibers, the tension can berelaxed which allows the fibers to assume their crimped shapes and fillthe space inside the shell. Unlike sponges that can also be compressed,the textured fibers can be wound onto spools in very long lengths, whichcan be continuously fed as a core in a core-sheath or wire coatingextrusion process. The sheath can be a molten polymer that isco-extruded and drawn with the stretched fibers. Individual units couldbe created by cutting the core sheath constructs to a desired length.Perforations can be created by piercing the tubing wall to form smallholes. Open pore sponges are very difficult to produce in a continuousform and hence would require the shell be formed as small discrete unitsinto which the sponge can be stuffed.

[0039] An additional advantage of fibrous scaffolding over sponges inprocessing is that the spool of fibers will be strong while an open cellsponge will be weak and will tear easily. This is an importantconsideration in miniaturization of the device. Small bunches of fiberscan be stretched, compressed or otherwise exposed to robust mechanicalprocessing. In contrast, small dimension sponges tear or break easilyand can only be subjected to gentle processing. Formation ofsub-millimeter devices necessarily subjects the filling to significantstresses in order to fit within the small dimensions of the shell.Miniaturization is very important in minimizing patient pain anddiscomfort following implantation of the device. Hence the use offibers, which can be compressed more substantially that an open-cellsponge, enables a smaller device which is preferable from the patient'sstandpoint.

[0040] At first glance it may appear desirable to fill the shell withsimple straight fibers. However, straight fibers would settle and bunchin the shell over time and would not provide a hospitable environmentfor ingress of large numbers of cells. Additionally, straight fiberwould require that the device be modified to prevent the fibers fromfall out of the device during handling. If the fibers were denselypacked or braided so as to provide an interference fit in the shellthere would not be sufficient porosity for cell colonization.Texturizing the fibers allows them to effectively fill space whilemaintaining porosities needed for colonization with high cell numberdensities. This low bulk density property of the texturized fibersenables an interference fit with the walls of the shell without havingto worry about compaction of the filling during storage and handling.

[0041] The textured fibers can either be filled into a preformed tube orthe tube can be extruded around the filaments. During the fillingprocess it may be desirable to stretch the filaments to a straightorientation. This radially compresses the fibers to a much smallerdiameter than they occupy when in a relaxed state. The void volume inthe lumen of the tube is preferably greater than 30% and more preferablygreater than 50%. Once relaxed the textured filaments should completelyfill the lumen of the device and should stay in place in the lumen dueto the compressive force exerted by the tubing walls on the filling.

[0042] A preferred process for generating the textured fiber filledtubes consists of extruding the tubing around the stretched filaments ina continuous manner. This can be accomplished by having the texturedfiber wound on a spool and fed under tension through the lumen of anextruder die as a core around which a sheath of wall polymer iscontinuously extruded. Perforations can later be drilled through thewall of the polymer either mechanically or using electromagneticradiation (e.g. laser ablation). It is especially desirable to adjustthe depth of drilling so that the wall is completely punctured but thefilling is not damaged. With electromagnetic radiation this can beaccomplished by provided just enough focused energy to ablate throughthe wall of the tube. Alternatively it is possible to fill a preformedtube by tying the textured fiber to a thin wire or needle and thendragging the textured filaments under tension through the tubing.Additionally, it is possible to fill a preformed tube by using apressure differential (e.g. vacuum or blown air) to pull the texturedfilament through the tubing. In this configuration the perforations inthe tube can be created either pre or post filling of the lumen. Thelength of the textured fiber filled tube is cut to be greater than a fewmillimeters and more preferably greater than 5 millimeters.

[0043] The lumen of the device is filled with an antigen, mixture ofantigens and optionally one or more cytokines, prior to implantation.The antigen can either be in a dry or wet form. Potential antigensinclude peptides, proteins, nucleotides, carbohydrates or even cells orcell fragments. The antigen or antigens can be bioavailable at the timeof implantation (for immediate release with optionally a portion in asustained release form) or designed to be bioavailable afterimplantation (e.g. 3 days after). The antigen or antigens can besupplied in a sustained release form, such as encapsulated inmicroparticles, can be supplied in a naked form or in combinationsthereof. One method by which antigen can be loaded is to suspend it in asuitable liquid which is then injected or pumped into the lumen of thefilled tube. The textured fiber filling must be under sufficientcompression as to stay in place through the convection of the fluid. Thefluid filled device can then be implanted or the filling fluid can bedehydrated or lyophilized prior to implantation leaving behind in thelumen of the filled device the desired antigen or antigens.Alternatively the textured fiber may be impregnated with the antigenetc. prior to insertion into the shell. The dehydrated system willrehydrate following implantation that will present the antigen in asuitable form for generating the desired immunomodulatory response. Aparticularly convenient site of implantation is subcutaneous insertiondirectly beneath the skin, however any site which offers access toantigen presenting cells, macrophages and other cells of the immunesystem is acceptable. Desired immunomodulatory responses can includeeither generation of humoral and/or cellular immunity against thedesired antigen or alternatively desensitization towards particularallergen or cell types.

[0044] Any specific antigen or combination of synthetic or naturalantigens may be employed as the antigenic substance for incorporation inthe immune modulation device and subsequent implantation in the animal.The antigens can be from bacterial, fungal, viral, cellular (e.g. fromparasites or in autoimmune treatments from animal tissue) or syntheticsources which contain at least one epitope to which the immune system ofthe animal will respond. In immunization the antigen is desired toinduce protective immunity to the animal to which it is administered.The antigen source can be preparations of killed microorganisms; livingweakened microorganisms; inactivated bacterial toxins (toxoids);purified macromolecules; recombinantly produced macromolecules and thelike. Preferably for mammals, the antigen or mixtures of antigens willbe derived from bacterial or viral sources with polyvalent antigenicdomains being present. Suitable bacterial antigen sources include, butare not limited to, Actinobacillus equuli, Actinobacillus lignieresi,Actinobaccilus seminis, Aerobacter aerogenes, Borrelia burgdorferi,Borrelia garinii, Borrelia afzelii, Babesia microti, Klebsiellapneumoniae, Bacillus cereus, Bacillus anthracis, Bordetella pertussis,Brucella abortus, Brucella melitensis, Brucella ovis, Brucella suis,Brucella canis, Campylobacter fetus, Campylobacter fetus intestinalis,Chlamydia psittaci, Chlamydia trachomatis, Clostridium tetani,Corynebacterium acne Types 1 and 2, Corynebacterium diphtheriae,Corynebacterium equi, Corynebacterium pyogenes, Corynebacterium renale,Coxiella burnetii, Diplococcus pneumoniae, Escherichia coli, Ehrlichiaphagocytophila, Ehrlichia equi, Francisella tularensis, Fusobacteriumnecrophorum, Giardia lambia, Granuloma inguinale, Haemophilusinfluenzae, Haemophilus vaginalis, Group b Hemophilus ducreyi,Lymphopathia venereum, Leptospira pomona, Listeria monocytogenes,Microplasma hominis, Moraxella bovis, Mycobacterium tuberculosis,Mycobacterium laprae, Mycoplasma bovigenitalium, Neisseria gonorrhea,Neisseria meningitidis, Pseudomonas maltophiia, Pasteurella multocida,Pasteurella hamemolytica, Proteus vulgaris, Pseudomonas aeruginosa,Plasmodium berghei, Plasmodium falciparum, Plasmodium malariae,Plasmodium ovale, Plasmodium vivax, Rickettsia prowazekii, Rickettsiamooseri, Rickettsia rickettsii, Rickettsia tsutsugamushi, Rickettsiaakari, Salmonella abortus ovis, Salmonella abortus equi, Salmonelladublin, Salmonella enteritidis, Salmonella heidleberg, Salmonellaparatyphi, Salmonella typhimurium, Shigella dysenteriae, Staphylococcusaureus, Streptococcus ecoli, Staphylococcus epidermidis, Streptococcuspyrogenes, Streptococcus mutans, Streptococcus Group B, Streptococcusbovis, Streptococcus dysgalactiae, Streptococcus equisimili,Streptococcus uberis, Streptococcus viridans, Treponema pallidum, Vibriocholerae, Yersina pesti, Yersinia enterocolitica and combinationsthereof. Suitable fungi antigen sources including, but are not limitedto, Aspergillus fumigatus, Blastomyces dermatitidis, Candida albicans,Crytococcus neoformans, Coccidioides immitis, Histoplasma capsulatum andcombinations thereof. Suitable viral antigen sources from viral sourcesinclude, but are not limited to, influenza, HIV, hanta virus (e.g. SinNombre virus), Mumps virus, Rubella virus, Measles virus, Smallpoxvirus, Hepatitis virus, (e.g. A, B, C, D, E), Rift Valley Fever (i.e.Plebovirus), viral encephalitis, (e.g. Eastern equine encephaliticvirus, St. Louis encephalitic virus, Western equine encephalitic virus,West Nile Virus), human papilloma virus, cytomegalovirus, polio virus,rabies virus, Equine herpes virus, Equine arteritis virus, IBR—IBPvirus, BVD—MD virus, Herpes virus (humonis types 1 and 2) andcombinations thereof. Suitable parasite antigen sources include, but arenot limited to, Schistosoma, Onchocerca, parasitic amoebas andcombinations thereof. Preferred infectious diseases that this device andmethod may provide prophylaxis against include viruses such asinfluenza, HIV, human papilloma, hepatitis, cytomegalovirus, polio andrabies; bacteria for example E. coli, Pseudomonas, Shigella, Treponemapallidum, Mycobacterium (tuberculosis and laprae), Chlamydia,Rickettsiae, and Neisseria; fungi such as Aspergillus and Candida; andparasitic multicellular pathogens.

[0045] Suppression of the immune response may also be desirable to treatconditions, such as allergies, or to prepare patients for the exposureto foreign antigens, such as for transplant. Inappropriate immuneresponses are believed to be the underlying etiology in a number ofautoimmune and other diseases, such as type I diabetes, rheumatoidarthritis, multiple sclerosis, uveitis, systemic lupus erythematosus,myasthenia gravis, and Graves' disease. By implanting in an individual adevice of the present invention containing the suspect antigen, entry ofcells primed to recognize the antigen can be induced to undergoapoptosis, and be eliminated from the immune system. Elimination ofprogenitor antigen-specific cells can permit the later transplant offoreign antigens without rejection.

[0046] Further utilities of the present invention include improvementsin the generation of polyclonal antibodies (immune serum) and nonclonalantibodies in laboratory animals and obtaining the desired isotype ofantibody so generated. In one embodiment, a procedure for preparingpolyclonal (immune serum) and monoclonal antibodies against an antigenavailable only in minute quantities can be performed by the device ofthe present invention. The device can be provided with a small amount ofthe rare antigen, in order to immunize the animal, after which spleencells can be harvested. This procedure offers an improvement overcurrent tedious and unpredictable method of introducing the rare antigendirectly into the spleen. Furthermore, the need for a boost immunizationmay be obviated by use of the device of the present invention, and, inaddition, an immune response will be generated more quickly. A shortenedtime required to immunize animals will allow the generation ofmonoclonal antibodes more rapidly. In another embodiment, immune cellsfor the production of hybridomas can be harvested from the device afterimmunization of an animal with an antigen provided within the device.This procedure can also be used to generate human monoclonal antibodies,by implanting a device of the present invention into an individual,loading the device with antigen, and then harvesting immune cells fromthe device for the production of hybridomas. The above-mentionedpolyclonal antibodies (immune serum) and monoclonal antibodies can beused for diagnosis, basic research, imaging and/or therapy. In anotherembodiment, human monoclonal antibodies can be generated using thedevice of the present invention implanted in a severe combinedimmunodeficiency (SCID) mouse, by the following procedure. First, humanperipheral blood lymphocytes are injected into a SCID mouse, wherein thehuman lymphocytes populate the murine immune system. After implantationof a device of the present invention comprising the desired antigenwhich is bioavailable after implantation, subsequent harvesting of cellsfrom the device will provide human B lymphocytes cells which can then beused to prepare hybridomas which secrete human antibodies against thedesired antigen.

[0047] A further utility of the device of the present invention is incollection of immune cells from a mammal for later reintroduction intothe mammal. Cells can be removed from the device, for example, byaspiration from the implanted device or collection from the device afterremoval from the body by dissolving the polymer matrix, subsequentstorage of the cells, for example by cryopreservation, andreintroduction into the mammal at a later time. This can be particularlyuseful for mammals undergoing whole body radiation therapy. A device ofthe present invention, without containing antigen, can be implanted andmaintained for a time sufficient to allow immune cells to migrate intothe device (e.g. seven to ten days). Subsequently the device or itscontents are removed and the cells contained therein cryopreserved.Following radiation therapy, the mammal can have the cells reintroducedinto the body, whereby the cells will reconstitute the immune system. Inanother embodiment of this utility, co-stimulatory factors such ascytokines which induce the proliferation of immune cells can beintroduced into the device to increase the yield of cells within thedevice, before harvesting. In a further embodiment, immune cellscollected from a device provided with antigen can be used for activeimmunization, wherein the cells can be stored and then reintroduced intothe mammal after, for example, a course of chemotherapy or othertherapeutic manipulation. In a still further embodiment, cells collectedfrom a device can be cyropreserved, and at a later time be exposed tothe antigen (for example, a cancer antigen) for ex-vivo propagation of Tcells prior to introduction into the body, for adoptive immunotherapy.

EXAMPLES

[0048] The following examples illustrate the construction of a texturedfiber filled device for generating an immunomodulatory response. Thoseskilled in the art will realize that these specific examples do notlimit the scope of this invention and many alternative forms of anantigen loaded textured fiber filled device could also be generatedwithin the scope of this invention.

Example 1

[0049] Textured Fibrous Filling

[0050] Fiber texturing was performed using a Techtex® HDC10 texturizer(Techniservice, 738 West Cypress Street, Kennett Square, Pa.19348-0817). Nine spools of 56 denier natural 90/10 glycolide-co-lactide(IV of about 1.1 deciliters per gram (dl/g) as measured in a 0.1 g/dlsolution of hexafluoroisopropanol at 25° C. The filaments had been drawnabout 5× (original length compared to final length). The filaments wereplaced on the creel and combined into a single 504 denier tow by runningthe drawn yarns together through a common eyelet. The individual yarnfilament diameters were between 12-20 μm. A pretension of 5-7 grams wasused for each yarn by passing them through the gate tensioner. The largeyarn tow was then passed over a heated godet with the separator roller(15 wraps) with the heated godet being set to a temperature of 130° C.This yarn tow was then fed into the stuffer box by two crimper rolls.The clearance between the stuffer box and rollers was 0.012 inches andthe temperature in the stuffer box was about 50° C. (the box was notheated, the elevated temperature of 50° C. came from the yarn, heated onthe godet). Uniformity of crimp texture is maintained through accuratecontrol of the crimped column height in the stuffer box. The columnheight control is provided by the optical sensor located in the stufferbox and signaling the take up winder inverter to speed up/slow down. Thestuffer box optical sensor was set to hole no. 8 from the top of thebox. After the stuffer box, the textured yarn tow passed through thegate tensioner set at 5 grams for combining and keeping all yarns in thetow under the same tension. The crimped yarn then passed the overfeedrolls to reduce high yarn tension prior to winding on the take upwinder. The take up winder speed was set at 170 m/min. An image of theresulting textured fiber is shown in FIG. 2.

Example 2

[0051] Membrane Formation

[0052] Membranes were formed from both poly(para-dioxanone) (PDO) and acopolymer of 35/65 epsilon-caprolactone/glycolide (CAP/GLY). Theinherent viscosity (dl/g) of the PDO and CAP/GLY, as measured in a 0.1g/dl solution of hexafluoroisopropanol (HFIP) 25° C., were 1.80 and1.30, respectively. All membranes were formed by extrusion using a{fraction (3/4)}-inch Brabender single-screw extruder (C.W. Brabender®Instruments, Inc., So. Hackensack, N.J.) under flowing nitrogen.Membranes with several inner and outer dimensions were formed. Extrusionconditions for the extruded membranes are shown in Table 1. Immediatelyfollowing exit from the die, all membranes were run through a 12-footcooling trough filled with chilled water at a temperature of 5-10° C.For the CAP/GLY membranes, short segments (˜2-3 ft.) were cut and hungfrom one end at room temperature to allow solidification andcrystallization of the polymer. TABLE 1 Extrusion conditions Die sizeScrew Take- Die × tip T_(zone1) T_(zone2) T_(zone3) T_(adapt.) T_(die)P_(block) P_(air) speed off OD ID Polymer (mil) (° C.) (° C.) (° C.) (°C.) (° C.) (psi) (psi) (rpm) (FTM) (mm) (mm) 35/65 170 × 138 140 145 145145 140 1900 0.1 12  20 2.0 1.5 CAP/GLY 35/65 102 × 83  140 145 145 145145 4480 0 4 18 1.03 0.83 CAP/GLY 35/65 53 × 40 140 145 145 145 140 43000.1 3 14 0.9 0.7 CAP/GLY 35/65 56 × 40 140 145 150 150 150 2470 0.3 4 340.65 0.45 CAP/GLY PDO 102 × 83  130 135 135 135 135 5000 0 5 20 1.030.83 PDO 102 × 83  145 150 150 150 150 3750 0 5 20 0.65 0.45

[0053] After extrusion, the membranes were cut to the desired length(2-2.5 cm) using a razor blade. Membrane perforations were formed atResonetics, Inc. (Nashua, N.H.) using an excimer laser (Lambda-PhysikEMG201MSC Excimer Laser) operating at a wavelength of 193 nm. The laserwas coupled to a Resonetics engineering workstation consisting of a maskprojection imaging beam delivery system and a three-axis (XYtheta)computerized motion control system. Hole sizes ranging between 100 and500 microns were formed through the membrane walls. Drilling parametersfor the different tubing are shown in Table 2. TABLE 2 Laser drillingconditions Fluence Pulse rate ˜ Etch rate Polymer OD/ID (mm/mm) (J/cm²)(Hz) (μm/pulse) 35/65 CAP/GLY   2.0 × 1.5., 10 50 0.63 0.9 × 0.7 35/65CAP/GLY 2.0 × 1.5 3.5 50 0.56 35/65 CAP/GLY 2.0 × 1.5 0.7 10 0.5 35/65CAP/GLY  1.03 × 0.83, 2 25 0.67 0.65 × 0.45 PDO  1.03 × 0.83, 2.6 50 0.50.65 × 0.45

Example 3

[0054] VLN Construct Formation

[0055] The textured fiber filling from Example 1 was placed inside themembranes discussed in Example 2 as follows. Textured fiber was attachedto a small needle or thin filament of wire and pulled through themembrane. The fiber was cut to the length of the membrane. Availableporosity was calculated from the volume of the inner lumen of themembrane, weight of textured yarn placed inside of the membrane, and thedensity of the fibers used. Table 3 shows several of the constructgeometries and resultant porosities. TABLE 3 Absorbable VLN constructscontaining textured fiber. Membrane OD/ID/length Hole diameter # Fiberweight ˜ Percent Composition (mm/mm/mm) (μm) holes (mg) porosity Sample# CAP/GLY 2.0/1.5/25 300 20 12 80% 1 CAP/GLY 2.0/1.5/20 300 16 10 80% 2CAP/GLY 2.0/1.5/20 300 12 10 80% 3 CAP/GLY 2.0/1.5/20 300 8 10 80% 4CAP/GLY 2.0/1.5/20 300 4 10 80% 5 CAP/GLY 2.0/1.5/20 not applicable 0 1080% 6 CAP/GLY 2.0/1.5/25 300 16 10 83% 7 CAP/GLY 2.0/1.5/25 300 16 1575% 8 CAP/GLY 2.0/1.5/20 300 20 8 83% 9 CAP/GLY 2.0/1.5/20 300 20 12 75%10 CAP/GLY 0.65/0.45/25 150 4 2 65% 11 CAP/GLY 0.65/0.45/25 150 12 2 65%12 CAP/GLY 0.65/0.45/25 150 20 2 65% 13 PDO 0.65/0.45/25 150 4 1.3 75%14 PDO 0.65/0.45/25 150 8 1.3 75% 15 PDO 0.65/0.45/25 150 12 1.1 80% 16PDO 0.65/0.45/25 150 16 1.3 75% 17

Example 4

[0056] Prior art (WO 99/44583) has demonstrated that a nonabsorbabledevice using a 25 mm length of silicone tubing with an internal diameterof 1.5 mm and outer diameter of 2 mm, fitted with a 25 mm-long segmentof hydroxylated polyvinyl acetate sponge induces a more robust immuneresponse to the influenza vaccine (in BALB/c mice) than traditionalintramuscular injections with and without the use of traditionaladjuvants such as Ribi. Similarly the device of the present inventionsuch as the absorbable, fiber-filled device described in Example 3(Sample #1) could be loaded with ˜100 ng of influenza antigen(FLUSHIELD® influenza virus vaccine, trivalent, Types A & B; obtainedfrom Henry Schein®, Melville N.Y.). Female BALB/c mice (6-8 weeks old)would be anesthetized with Avertin. One device per animal could beinserted through a 0.5-cm dorsal midline incision on day 1.

[0057] At appropriate intervals post-immunization the mice could be bledand the sera tested for influenza-specific humoral response, usingconventional ELISA or other appropriate protocols to determine immuneresponse. The optimum dosage of antigen of the device could bedetermined by developing dose response curves at appropriate timeintervals post implantation. Similarly, the cell population in thedevice could be determined at appropriate intervals (e.g. days 3, 7, 10etc.) to verify the migration of cells into the device, cell types inthe device and optimum configuration of holes etc. to provide the mostadvantageous conditions for immune modulation in any animal with aparticular antigen (or antigens).

We claim:
 1. An immune modulation device that is suitable for use inmodulating an immune response in animals, comprising an impermeablebiocompatible shell having an outer surface with plurality of pores ofsuitable size to allow the ingress and egress of immune cells and saidimpermeable biocompatible shell having an interior lumen, abiocompatible fibrous scaffolding being disposed within said interiorlumen.
 2. The immune modulation device of claim 1 wherein the fibrousscaffolding has a porosity of from about 25 percent to about 95 percent.3. The immune modulation device of claim 1 wherein the fibrousscaffolding is made from filaments with a diameter of less than 20microns.
 4. The immune modulation device of claim 1 wherein the fibrousscaffolding is made from filaments with a denier of from about 0.2 toabout
 10. 5. The immune modulation device of claim 1 wherein the fibrousscaffolding is made from filaments with a denier of from about 0.8 toabout
 6. 6. The immune modulation device of claim 1 wherein the fibrousscaffolding is made from a bundle of filaments having a total denier offrom about 20 to about 400 denier.
 7. The immune modulation device ofclaim 1 wherein the fibrous scaffold is made from a textured yarn. 8.The immune modulation device of claim 7 wherein the textured yarn isselected from the group consisting of bulked yarns, coil yarns, corebulked yarns, crinkle yarns, entangled yarns, modified stretch yarns,nontorqued yarns, set yarns, stretch yarns and torqued yarns andcombinations thereof.
 9. The immune modulation device of claim 1 whereinthe immune modulation device has a three dimensional shape selected fromthe group consisting of spherical, cylindrical, rectangular andrhomboidal.
 10. The immune modulation device of claim 8 wherein theimmune modulation device is cylindrical in shape.
 11. The immunemodulation device of claim 10 wherein the cylindrically shaped immunemodulation device has an outer diameter of less than 1 millimeter. 12.The immune modulation device of claim 11 wherein the cylindricallyshaped immune modulation device has an outer diameter of less than 750microns.
 13. The immune modulation device of claim 10 wherein thecylindrically shaped immune modulation device has a wall thickness ofless than 250 microns.
 14. The immune modulation device of claim 13wherein the cylindrically shaped immune modulation device has a wallthickness of less than 150 microns.
 15. The immune modulation device ofclaim 1 wherein the pores on the outer surface of the immune modulationdevice comprise less than 25 percent of the outer surface.
 16. Theimmune modulation device of claim 15 wherein the pores range in sizefrom about 10 to about 500 microns.
 17. The immune modulation device ofclaim 1 wherein the immune modulation device is bioabsorbable.
 18. Theimmune modulation device of claim 17 wherein the bioabsorbable immunemodulation device is made from a polymer selected from the groupconsisting of aliphatic polyesters, poly(amino acids),copoly(ether-esters), polyalkylenes oxalates, polyamides, tyrosinederived polycarbonates, poly(iminocarbonates), polyorthoesters,polyoxaesters, polyamidoesters, polyoxaesters containing amine groups,poly(anhydrides), polyphosphazenes, biomolecules and blends thereof. 19.The immune modulation device of claim 18 wherein the bioabsorbableimmune modulation device is made from an aliphatic polyester.
 20. Theimmune modulation device of claim 19 wherein the aliphatic polyester isselected from the group consisting of homopolymers and copolymers oflactide (which includes lactic acid, D-, L- and meso lactide), glycolide(including glycolic acid), ε-caprolactone, p-dioxanone(1,4-dioxan-2-one), trimethylene carbonate (1,3-dioxan-2-one), alkylderivatives of trimethylene carbonate, delta-valerolactone,beta-butyrolactone, gamma-butyrolactone, ε-decalactone, hydroxybutyrate,hydroxyvalerate, 1,4-dioxepan-2-one (including its dimer1,5,8,12-tetraoxacyclotetradecane-7,14-dione), 1,5-dioxepan-2-one,6,6-dimethyl-1,4-dioxan-2-one, 2,5-diketomorpholine, pivalolactone,gamma, gamma-diethylpropiolactone, ethylene carbonate, ethylene oxalate,3-methyl-1,4-dioxane-2,5-dione, 3,3-diethyl-1,4-dioxan-2,5-dione,6,8-dioxabicycloctane-7-one and polymer blends thereof.
 21. The immunemodulation device of claim 20 wherein the shell is made from analiphatic polyester selected from the group consisting of homopolymersand copolymers of lactide (which includes lactic acid, D-, L- and mesolactide), glycolide (including glycolic acid), ε-caprolactone,p-dioxanone (1,4-dioxan-2-one), trimethylene carbonate(1,3-dioxan-2-one), alkyl derivatives of trimethylene carbonate,1,4-dioxepan-2-one (including its dimer1,5,8,12-tetraoxacyclotetradecane-7,14-dione), 1,5-dioxepan-2-one,6,6-dimethyl-1,4-dioxan-2-one and polymer blends thereof.
 22. The immunemodulation device of claim 20 wherein the shell is made from analiphatic polyester selected from the group consisting ofpoly(p-dioxanone), glycolide-co-ε-caprolactone,glycolide-co-trimethylene carbonate, glycolide-co-1,5-dioxepan-2-one,6,6-dimethyl-1,4-dioxan-2-one and blends thereof.
 23. The immunemodulation device of claim 1 wherein the biocompatible fibrousscaffolding is made from an aliphatic polyester selected from the groupconsisting of homopolymers and copolymers of lactide (which includeslactic acid, D-, L- and meso lactide), glycolide (including glycolicacid), ε-caprolactone, p-dioxanone (1,4-dioxan-2-one), trimethylenecarbonate (1,3-dioxan-2-one), alkyl derivatives of trimethylenecarbonate, 1,4-dioxepan-2-one (including its dimer1,5,8,12-tetraoxacyclotetradecane-7,14-dione), 1,5-dioxepan-2-one,6,6-dimethyl-1,4-dioxan-2-one and polymer blends thereof.
 24. The immunemodulation device of claim 23 wherein the biocompatible fibrousscaffolding is made from an aliphatic polyester selected polyglycolide,poly(p-dioxanone), glycolide-co-ε-caprolactone,glycolide-co-trimethylene carbonate and glycolide-co-lactide.
 25. Theimmune modulation device of claim 1 wherein the shell is made frompoly(p-dioxanone) and the fibrous scaffolding is made from a copolymerof about 90 weight percent glycolide and about 10 weight percentlactide.
 26. The immune modulation device of claim 25 wherein thefibrous scaffolding is made from a textured yarn.
 27. The immunemodulation device of claim 1 wherein the shell is made from a copolymerof from about 35 to about 45 weight percent epsilon-caprolactone andfrom about 55 to about 65 weight percent glycolide and the fibrousscaffolding is made from a copolymer of about 90 weight percentglycolide and about 10 weight percent lactide.
 28. The immune modulationdevice of claim 27 wherein the fibrous scaffolding is made from atextured yarn.
 29. The immune modulation device of claim 1 whichcontains one or more antigens.
 30. The immune modulation device of claim29 wherein the antigen is selected from the group of natural antigens,synthetic antigens and combinations thereof.
 31. The immune modulationdevice of claim 30 wherein the natural antigen is derived from a microbeselected from the group consisting of Actinobacillus equuli,Actinobacillus lignieresi, Actinobaccilus seminis, Aerobacter aerogenes,Borrelia burgdorferi, Borrelia garinii, Borrelia afzelii Babesiamicroti, Klebsiella pneumoniae, Bacillus cereus, Bacillus anthracis,Bordetella pertussis, Brucella abortus, Brucella melitensis, Brucellaovis, Brucella suis, Brucella canis, Campylobacter fetus, Campylobacterfetus intestinalis, Chlamydia psittaci, Chlamydia trachomatis,Clostridium tetani, Corynebacterium acne Types 1 and 2, Corynebacteriumdiphtheriae, Corynebacterium equi, Corynebacterium pyogenes,Corynebacterium renale, Coxiella burnetii, Diplococcus pneumoniae,Escherichia coli, Ehrlichia phagocytophila, Ehrlichia equi, Francisellatularensis, Fusobacterium necrophorum, Giardia lambia, Granulomainguinale, Haemophilus influenzae, Haemophilus vaginalis, Group bHemophilus ducreyi, Lymphopathia venereum, Leptospira pomona, Listeriamonocytogenes, Microplasma hominis, Moraxella bovis, Mycobacteriumtuberculosis, Mycobacterium laprae, Mycoplasma bovigenitalium, Neisseriagonorrhea, Neisseria meningitidis, Pseudomonas maltophiia, Pasteurellamultocida, Pasteurella hamemolytica, Proteus vulgaris, Pseudomonasaeruginosa, Plasmodium berghei, Plasmodium falciparum, Plasmodiummalariae, Plasmodium ovale, Plasmodium vivax, Rickettsia prowazekii,Rickettsia mooseri, Rickettsia rickettsii, Rickettsia tsutsugamushi,Rickettsia akari, Salmonella abortus ovis, Salmonella abortus equi,Salmonella dublin, Salmonella enteritidis, Salmonella heidleberg,Salmonella paratyphi, Salmonella typhimurium, Shigella dysenteriae,Staphylococcus aureus, Streptococcus ecoli, Staphylococcus epidermidis,Streptococcus pyrogenes, Streptococcus mutans, Streptococcus Group B,Streptococcus bovis, Streptococcus dysgalactiae, Streptococcusequisimili, Streptococcus uberis, Streptococcus viridans, Treponemapallidum, Vibrio cholerae, Yersina pesti, Yersinia enterocolitica,Aspergillus fumigatus, Blastomyces dermatitidis, Candida albicansCrytococcus neoformans, Coccidioides immitis, Histoplasma capsulatum,influenza viruses, HIV, hanta viruses, human papilloma virus,cytomegalovirus , polio virus, rabies virus, Equine herpes virus, Equinearteritis virus, IBR—IBP virus, BVD—MD virus, Herpes virus (humonistypes 1 and 2), Mumps virus, Rubella virus, Measles virus, Smallpoxvirus, Hepatitis viruses, Rift Valley Fever virus, viral encephalitises,Schistosoma, Onchocerca, parasitic amoebas and combination thereof. 32.A method of modulating the immune system in an animal to an antigen byimplanting within the body of said animal an immune modulation devicecomprising an impermeable biocompatible shell having an outer surfacewith plurality of pores of suitable size to allow the ingress and egressof immune cells and said impermeable biocompatible shell having aninterior lumen, a biocompatible fibrous scaffolding being disposedwithin said interior lumen, said interior lumen containing a quantity ofantigen sufficient to provoke an immune response.
 33. The method ofclaim 32 wherein the antigen is bioavailable at the time the immunemodulation device is implanted into said animal.
 34. The method of claim32 wherein the antigen becomes bioavailable after the immune modulationdevice is implanted into said animal.
 35. The method of claim 32 whereinthe quantity of antigen and the timing of the bioavailability of saidantigen within the immune modulation device relative to the time ofimplantation of the immune modulation device into said animal results ininducing or enhancing the immune response to said antigen.
 36. Themethod of claim 32 wherein the quantity of antigen and the timing of thebioavailability of said antigen within said immune modulation devicerelative to the time of implantation of said immune modulation deviceinto said animal is sufficient to result in suppressing or downregulating an existing or potential immune response to said antigen. 37.The method of claim 32 wherein multiple antigens are present in thedevice in an amounts sufficient to provoke an immune response.
 38. Themethod of claim 32 wherein only a portion of the antigen is bioavailableat a time the immune modulation device is implanted.
 39. The method ofclaim 37 wherein only a portion of the multiple antigens arebioavailable at a time the immune modulation device is implanted. 40.The method of claim 32 wherein only a portion of the antigen isbioavailable at 3 days after implantation of the immune modulationdevice.
 41. A method of obtaining immune cells from an animal comprisingharvesting immune cells from an immune modulation device comprised of animpermeable biocompatible shell having an outer surface with pluralityof pores of suitable size to allow the ingress and egress of immunecells and said impermeable biocompatible shell having an interior lumen,a biocompatible fibrous scaffolding being disposed within said interiorlumen, said interior lumen having therein a quantity of antigen orchemotatic agent sufficient to provoke an immune response that wasimplanted within an animal time sufficient to allow immune cells tomigrate into the immune modulation device.
 42. The method of claim 41wherein the harvested cells are reintroduced to animals.
 43. A method ofmanufacturing an immune modulation device having an impermeablebiocompatible shell having an outer surface and an interior lumencomprising placing a fibrous scaffolding within an interior lumen of theimpermeable biocompatible shell; and forming pores within saidbiocompatible impermeable shell of suitable size to allow the ingressand egress of immune cells.
 44. The method of claim 43 wherein thebiocompatible impermeable shell has a cylindrical shape having a firstend and a second end.
 45. The method of claim 44 wherein the first endof the biocompatible impermeable shell is sealed.
 46. The method ofclaim 45 wherein the end is sealed after the fibrous scaffolding isplaced within the biocompatible impermeable shell.
 47. The method ofclaim 46 wherein the biocompatible impermeable shell is made of apolymer.
 48. The method of claim 47 wherein the end of the biocompatibleimpermeable shell is crimped and heated to seal said first end.
 49. Themethod of claim wherein 43 wherein at least one antigen is insertedwithin the interior lumen in an amount sufficient to provoke an immuneresponse.
 50. The immune modulation device of claim 43 wherein the poresare formed by laser ablation.
 51. The immune modulation device of claim43 wherein the impermeable biocompatible shell having an outer surfaceand an interior lumen is formed by extruding a biocompatible polymer.52. The immune modulation device of claim 10 wherein the cylinder has afirst end and a second end, said first end being sealed.